The objectives of this project are to improve the methods used to diagnose and to treat microbic plaque infections that destroy teeth and their supporting structures. Plaques from patients that have dental caries and destructive periodontitis are studied to determine the prevalence of Streptococcus mutans, various actinomyces, and motile forms. The prevalence of these populations and the appearance of lesions are followed as patients follow various experimental programs of dietary, mechanical and chemical therapy directed towards elimination and control of the potentially odontopathic microorganisms mentioned above. New and innovative cultural and microscopic methods are used to detect the presence of the microbes under consideration. Antibacterial agents and fluoride compounds are administered as adjuvants to conventional oral hygiene procedures and regulation of eating patterns.